Machine for making noncircular tubing with helically wound strip



Feb. 28, 1956 P. M. PADGETT MACHINE FOR MAKING NONCIRCULAR TUBING WITH HELICALLY WOUND STRIP 5 Sheets-Sheet 1 Filed May l0 1951 WML ATTORNEY Feb. 28, 1956 P. M. PADGETT 2,736,285-- MACHINE FOR MAKING NONCIRCULAR TUBING WITH HELICALLY WOUND STRIP Filed May l0, 1951 5 Sheets-Sheet 2 f FIG. 2.

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INVENTOR QWMQ mx BY m ATTORNEY Feb. 28, 1956 P. M. PADGETT 2,736,285

MACHINE FOR MAKING N'ONCIRCLAR TUBING WITH HELICALLY WOUND STRIP Filed May 10, 1951 5 Sheets-Sheet 3 ATTORNEY Feb. 28, 1956 P. M. PADGETT MACHINE FOR MAKING NONCIRCULAR TUBING WITH HELICALLY WOUND STRIP 5 Sheets-Sheet 4 Filed May lO, 1951 b 5 l MM M, M a M M f a, W y 7 3 :z: M II l' l W w y Pn Ih n NVEN' W7 KTM ATTORNEY Feb. 28, 1956 P. M. PADGETT 2,736,285

MACHINE FOR MAKING NONCIRCULAR TUBING WITH HELICALLY WOUND STRIP Filed May lO, 1951 5 Sheets-Sheet 5 MNA 9W ATTORNEYS MACHINE FOR MAKING N ONCIRCULAR TUBING WITH HELICALLY WOUND STRIP Philip M. Padgett, Newark, N. J., assigner, by mesne assignments, to Titeilex Inc., Newark, N. J., a corporation of Massachusetts Application May 10, 1951, Serial No. 225,541 3 Claims. (Cl. 113-35) This invention relates to apparatus for making flexible metal tubes of polygonal cross section andmore especially of the generally rectangular cross section used for Wave guides in electronic equipment. These wave guides have flat sides of different width, the narrower sides being somewhat less than half the width of the wider sides. When the tubes are made by wrapping a longitudinally corrugated strip in a helix around a rotating mandrel, the large differences in the radial thickness of the mandrel at diierent phase angles create special problems.

For small sizes of wave guides it has been practical to impart a reverse bend to the formed strip around a roller that guides the strip as it wraps on a continuously rotating mandrel. Apparatus for making such exible tubes on a continuously rotating mandrel is disclosed in my copending application Ser. No. 58,472, tiled November 5, 1948, now Patent No. 2,618,233, issued November 18, 1952. For tubes of larger size it is necessary to use wider strip material of heavier gauge and with a deeper longitudinal corrugation. Such strips cannot be given the reverse bend used in making the smaller tubes without danger of collapsing the formed strip, or tearing the metal when adequately restrained against collapsing.

It is an object of this invention to provide improved apparatus for making helically Wound, llexible tubes of polygonal cross section, particularly the sections used for wave guides; and for making such tubes in large sizes and with the gauge of metal suitable for large sizes. The invention obtains this result by placing rollers at angularly spaced locations around the mandrel in positions to guide the strip, and to seam and strip the tube; and during each revolution of the mandrel changing the angular positions of the rollers in such a way as to guide the engagement of the strip edges across the flat sides of the mandrel as the strip is laid on the flat sides by the rotation of the mandrel.

In the preferred construction of the invention, the rollers around the mandrel are carried by a frame that oscillates about an axis substantially coincident with the axis of rotation of the mandrel to change the angular positions of the rollers. They are connected to supports movable with respect to the frame to shift the rollers toward and from the axis of the mandrel to compensate for the change in the radial dimensions of the portions of the mandrel irnrnediately under each roller. In the embodiment of the invention described herein, the mandrel is rotated intermittently and is stopped while the rollers travel around it in the direction opposite to its direction of rotation.

Other features of the invention relate to cam mechanism that controls the positions of the rollers with respect to the mandrel and to the tensioning of the strip while the first roller guides the edge of a new convolution into engagement with the previous convolution across a flat side of the mandrel.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like `sited States Patent C ICC reference characters indicate corresponding parts in all the views.

Figure 1 is a diagrammatic perspective view showing the preferred embodiment of the invention;

Figure 2 is an enlarged detail view of the mandrel and tube forming apparatus of the machine shown in Figure l.

Figures 3 to 5 are reduced scale views of the mandrel and tube forming apparatus of Fig. 2 with the parts in the successive positions which they occupy during a cycle of operation of the machine.

Figure 6 is an end View of the apparatus shown in Figure 2, with parts broken away to show certain of the underlying structure.

Figure 7 is an enlarged view, partly in section, showing the way in which the arms are connected with the oscillating frame.

Figures 8, 9 and 10 are greatly enlarged views showing the wrapping and seaming of the tube on the mandrel.

The machine includes a main frame 10 having a base 11 on which the machine is supported from the floor or other underlying surface. At the upper end of the frame there is a composite mandrel comprising a mandrel axle 13 and a mandrel body 14 which are supported for rotation about their longitudinal axis. The mandrel body 14 is of generally rectangular cross section, with ilat sides joined by rounded corners, and the shorter sides are somewhat less than one-half the length of the longer sides to provide a tube having desirable characteristics for use as a Waveguide.

The mandrel axle 13 has supports 15 spaced from one another along the length of the axle for keeping the tube that is formed by the machine, in substantial alignment with the mandrel for a portion of the length of the tube immediately beyond the mandrel body 14. These supports 15 have tapered rearward faces for guiding the end of the tube on to the supports as it is progressively stripped from the mandrel. A continuous mandrel body equal in length to the mandrel axle 13 can be used in place of the spaced supports 15.

The mandrel axle 13 has a sprocket 17 secured to its rearward end, and this sprocket is driven from another sprocket 19 through a chain 20. The sprocket 19 is secured to a shaft 22 which is driven by a Geneva movement, one element of which is attached to the shaft 22 and the other element of which is attached to a parallel shaft 25.

Onthe shaft 25 there is a gear 26 which is driven from another gear 27 through an idler 28. The purpose of the idler is to make the gears 26 and 27 rotate in the same direction. The gear 27 is fixed to a cam shaft 30 having a sprocket 31 at one end driven from another sprocket 32 through a chain 33. On the cam shaft 30 there is a cam 35 which operates a cam follower 36, the purpose of which will be explained in connection with the oscillation of the roller-supporting frame of the machine.

The sprocket 32 is secured to a shaft 37 with two other sprockets 38 and 39. A jack shaft 41 has a sprocket 42 which is driven from the sprocket 38 through a chain 44. This jack shaft 41 drives a pulley 46 through which power is supplied to a forming unit 48 by a V-belt 49. The other sprocket 39 on the shaft 37 is driven from a drive shaft 51 by a chain 52 passing around a sprocket 53 on the drive shaft. The drive shaft 51 can be connected to a transmission 55 by engaging a clutch 56. This clutch 56 is engaged and disengaged by a manually operated lever 58. An electric motor 60 supplies power to the transmission 55.

When the clutch 56 is engaged, the motor 60 drives the shaft 51, and through the various sprocket and chain connections drives the shafts 25, 41, and all other intermediate shafts with continuous motion. The rotation of the shaft 25 is transmitted to the shaft 22 as an intermittent rotary motion through the Geneva movement 23. This causes the arbor 14 to move intermittently through successive angular movements of 90, there being four such movements for each revolution of the mandrel with substantial periods of dwell after two of the movements, and little or no dwell after the other two movements. All movements are in the same direction. This motion is counterclockwise in Figure l.

rIhe rotation of the jack shaft 41 is transmitted to the forming unit 4S. There are a plurality of roll stands in the forming unit 48 and a metal strip 62 advances through these roll stands successively and is progressively formed to the cross section desired for making the tube on the mandrel. The construction of the forming unit 4S is preferably similar to that shown in my co-pending application Serial No. 58,472, now Patent No. 2,618,233, issued November 18, 1952. All of the rolls of the forming unit 48 are driven through gearing from a pulley 64 which is rotated by the belt 49, but there is a clutch associated with the pulley 64 which slips before enough power has been supplied to move the strip 62 through the forming unit 48. The pulley 64 and its associated clutch are adjusted to supply almost enough power to advance the strip 62 through the forming unit 48 and a small addi tional pull on the formed strip by the rotation of the mandrel 14 causes the strip 62 to advance through the forming unit 48.

When the clutch 56 is disengaged, the apparatus can be operated manually, to facilitate the initial threading of the machine, by means of a hand wheel 66 connected to a sprocket 67 that transmits movement through a chain 68 to a lower sprocket 70 secured to the shaft 51.

After leaving the forming unit 48, the formed strip 62 passes through pairs of guide rolls 72 located at spaced regions along a frame element or angle bar 74. Beyond the last pair of guide rolls 72, the formed strip passes under a nal guide roll 75, carried by the bar 74, and from this guide roll 75, the strip passes to the mandrel. The apparatus also supplies to the mandrel a wire 77 which is unreeled from a spool 7S carried by a bracket 79 at the base of the machine. This wire 77 is pulled through straightening dies 81 and across guide rolls S2 by the rotation of the mandrel 14 on which the wire wraps in a helix with convolutions under those of the strip 62. Copper wire has been found most suitable for the purpose.

The forming unit 48 is supported on rails 83 along which it can slide toward and from the mandrel. Such movement of the unit 4S along the rails tightens and loosens the belt 49 and partially controls the strip feed by loosening the belt until it slips and stops the operation of the forming unit at times when the bar 74 pushes the unit 48 away from the mandrel.

The apparatus also includes an oscillating frame 81 supported by suitable bearing means on which the frame is movable about an axis substantially coincident with the axis of rotation of the mandrel 14. This frame 81 'carries a plurality of arms and rollers which will be explained in connection with Figure 2. For the present, it is suiiicient to understand that the frame 81 has a bracket 33 rigidly secured to it, and that this bracket 83 is joined to a link 34 by a pivot 85. The other end of the link 84 has a pivotal connection 87 to the upper end of a lever 88 which'is supported from the frame of the machine by a fulcrurn pivot 90. The lower end of the lever S8 is connected to one end of a group of tension springs 92 by rods 93. The other ends of these tension springs are connected with the fixed frame 10 of the machine.

The pull of the springs 92 urges the lever SS to rock clockwise about its fulcrum pivot 90; but such rocking movement is controlled by the cam follower 36 which is connected to the lever 8S by a bracket 95. The cam 35 periodically displaces the cam follower 36, toward the left in Figure l, to rock the lever 88 counterclockwise against the tension of the springs 92. Thus the combined action of the cam 35 and the springs 92 causes the lever 88 to oscillare back and forth about its fulcrum pivot 90, and to impart an oscillation to the frame S1.

The cam 35 is shaped, however, with a portion of its face of circular contour about its axis of rotation so that there is a substantial period of dwell for the lever S3 after each complete oscillation. The phase angle of the cam 35 is so correlated with the Geneva movement 23 that the oscillations of the frame 81 are in a predetermined, timed relation with the intermittent movements of the mandrel 14. This relation will be explained more fully in connection with Figures 2 to 5.

Figure 2 shows the frame 81 with five brackets 97 rigidly connected to it. The bracket 33 is connected between two of the brackets 97, but it is sufficient that this bracket 3 be connected to any rigid part of the frame S1, or the link 84 can be pivotally connected to one of the brackets 97 without using the additional bracket 83. The construction is made in the manner illustrated in order to permit the link 84 to be connected to the frame 81 at different locations for imparting different degrees of angular movement to the frame S1 to accommodate mandrels of different size.

There are arms 99 carried by four of the brackets 97 and connected to their brackets by pivot bearings 100. There are rollers 101, 102, 103 and 104 carried by the respective arms 99 at angularly spaced regions around the mandrel 14.

Each of the rollers 10i- 104 has an axle carried by a yoke 106 which extends from a mounting block assembly 107 by which the yoke is fastened to the arm 99. The yoke 106 of the iirst roller 101 has a connector 109 by which it is pivotally secured to the angle bar 74. This connector 109 makes the angle bar 74 moves lengthwise in proportion to any horizontal component of movement of the roller 101 and thus advances or retracts the strip forming unit 48 to compensate for horizontal components of movement of the roller 101.

Each of the rollers 10i-104 has a cam follower portion 126 that bears against the surface of the mandrel 14 beyond the region at which the strip 62 and wire 77 wrap around the mandrel. These cam follower portions are of a slightly larger diameter than the rollers 10i-104 so that the faces of the rollers clear the mandrel by a distance slightly greater than the thickness of the strip 62, as will be more fully explained hereinafter, in connection with Figure 6.

The arm 99 that carries each of the rollers 10i-104 also has a cam follower that bears against the face of an inside cam 111 which moves the rollers 10i-164 inward to keep them close to the mandrel as the rotation of the mandrel brings portions of smaller radial width under the respective rollers. This construction, also, will be more fully explained in connection with Fig. 6.

As the strip 62 moves beyond the guide roll 75, it passes to the mandrel 14 where it is guided by the roller 101 to insure engagement of the upturned ange at one side of the strip with the folded over edge of the other side of the strip in the next adjacent convolution on the mandrel. With the mandrel in the position shown in Y Figure 2, the rotation of the mandrel is stopped, and the frame S1 oscillates toward the strip supply, that is, clockwise in Fig. 2. This movement causes the first roller 101 to move along the wide flat side of the stationary mandrel 14 and to guide the new length of strip over that surface into engagement with the last convolution already on the mandrel. As the roller 101 moves toward the right across the flat side of the mandrel, the angle bar 74 is pushed back so that the pull on the strip is maintained while the roller 101 is moving in a direction opposite to that of the strip feed.

The clockwise rotation of the frame 81 carries the second roller 102 across the short flat side of the mandrel and around the cornerto `the long at side into the position shown in Figure 3. A guide finger 113 at one end of a lever arm 114 travels along the strip immediately ahead of the roller 102 for the purpose of maintaining the engaged edges of the strip substantially upright as they approach the roller 102 which starts the bending over of edges to seam the tube.

This guide iinger 113 is adjustable with respect to the lever arm 114, but is held in a fixed relation to the lever arm after being adjusted, and the guide finger is pressed against the surface of the strip 62 by the tension of a spring 116 which is connected at its upper end to the lever 114 above a fulcrum unit 118 by which the lever arm 114 is supported from a bracket on the adjacent arm 99. The end of the spring 116 is connected to the pivot bearing 100 at the end of the arm which carries the roller 103.

This movement of the roller 102 across the short` side of the mandrel and around the corner at the upper end of the short side of the mandrel performs the first part of the seaming operation. The next roller 103 may complete the seaming operation, or the rollers 103 or 104 can be shaped so that seaming of the tube is partially completed by the roller 103 and finished by the roller 104.

The apparatus can be made with more than four rollers 101-104, or with only three such rolls, but there should be not less than three because these rollers also function to strip the tube from the mandrel and the stripping action should be distributed around the perimeter of the mandrel for best results.

Figure 3 shows the positions of the parts when the frame 81 has completed a clockwise oscillation during one of the long dwell periods of the mandrel. The next movement in the cycle of the machine is an angular movement of the mandrel 14 through 90 and a simultaneous movement of the frame 81 in the same direction as the mandrel turns. This rotation or angular movement of frame $1 is at a slower rate than the angular movement of the mandrel, however so that the first roller 101 travels around the corner of the mandrel and guides the strip as it wraps around the mandrel during this 90 degrees of mandrel rotation.

Figure 4 shows the position of the mandrel shortly after it begins its rotation from the dwell position that it occupied in Figure 3. The frame 81 is turning in the same direction as the mandrel 14 but at a somewhat slower rate so that the rollers 101- 104 have relative clockwise movement around the mandrel in Figure 4. This causes the first roller 101 to travel around the corner of the mandrel into position to guide the strip 62 as the narrow flat side of the arbor moves up into line with the direction in which the strip 62 is supplied to the mandrel.

Figure 5 shows the positions of the parts at the end of the forward oscillation of the frame 81 and at the end of the quarter revolution through which the mandrel is moving in Fig. 4. The upper, narrow flat side of the mandrel is substantially in line with the supply strip 62, and the first roller 101 has advanced, relative to the mandrel, across the narrow flat side and guided the new section of the strip into engagement with the preceding convolution on the mandrel.

There is no substantial dwell of the mandrel in the position illustrated in Figure 5, or only a short dwell, the Geneva movement being constructed so as to cause the mandrel to turn promptly through another quarter revolution into the position shown in Figure 2. During this movement of the mandrel, the frame 81 turns in the same direction as the mandrel to bring the parts into the positions shown in Figure 2.

Figure 6 is an end view, partly broken away to show the rollers and the cam followers that move the rollers away from and toward the axis of the mandrel as the radial width of the mandrel under the respective rollers changes. The construction that leaves the arms free to swing is shown in Fig. 7 on a larger scale than in Fig. 6.

6 Each of these pivot bearings includes a pin which extends through the arm 99 and through a bushing 121. This bushing 121 has a shoulder portion 122 which serves as a spacer between the bracket 97 and the arm 99. There is also a thrust washer 123 which adds to the spacing of the bracket 97 and the arm 99. The bushing 121 preferably fits with a press fit in the bracket 97 and the pivot pin 120 has threads at both ends with nuts 124 for preventing axial displacement ofthe parts. This construction leaves the arm 99 free to swing on the pin 120 as a fulcrum.

Referring further to Fig. 6, the roller 101 has a cam follower portion 126 which bears against the face of the mandrel 14 beyond the region at which the wire and strip are wrapped around the mandrel. This cam follower portion 126 is displaced by the mandrel which acts as a cam for moving the follower portion 126 and the entire roller 101 in such a way as to always maintain a predetermined clearance between the corrugated face of the roller 101 and the surface of the mandrel on which the strip wraps. This clearance is preferably slightly greater than the thickness of the strip 64 so that the roller holds the strip against the mandrel but does not exert any rolling pressure which would effect the thickness *of the strip.

A stud 128 extending rearwardly from the arm 99 (toward the left in Fig. 6), serves as an axle for another cam follower 129 which bears against the surface of the inside cam 111. This inside cam is shaped to correspond to the size of the mandrel and it'provides a positive displacement of the roll 101, and other corresponding rolls around the mandrel, so that the rolls move inwardly closer to the axis of the mandrel as the radial width of the mandrel under them decreases. The angular possition of the inside cam 111 corresponds with the angular position of the mandrel with respect to the wide and narrow straight sides of the mandrel. This inside cam 111 is attached to the mandrel support so that it always remains in the same position, that is, at the same phase angle, with respect to the mandrel and it is not affected by oscillating movement of the frame 81. The cam 111 can be detached and replaced with a cam of different size or shape when a different mandrel is to be used.

Near the lower end of each arm, the mounting bracket assembly 107 is connected to the arm on one side of a slit 132 (Fig. 2). The width of this slit of the arm can be adjusted by screws 134 and 135 (Fig. 7). The screw 135 threads through the portion of the arm above the slit 132 and has its end abutting against the face on the opposite side of the slit. The other screw 134 extends freely through a hole in the portion of the arm above the slit and threads into the portion of the arm below the slit so that the tightening of this screw pulls the slit closer together, it being necessary, of course, to back off the other screw 135. This adjustment is the same as in my copending application Serial No. 58,472, referred to above, and no further explanation of itis necessary for a com plete understanding of this invention.

The mounting bracket assembly 107 which carries the roller 101 and its cam follower portion 126 is located above the slit 132, whereas the cam follower 129 is carried by the portion of the arm 99 below the slit 126. Thus the adjustment of the slit width provides an accurate control for lining up the axes of the roll 101 and the cam follower 129.

Figure 8 shows the roller 101 which guides the strip 62 into its initial contact with the mandrel 14. There are a plurality of circumferentially extending grooves in the face of the roller 101. These include a groove 142 for guiding the wire 77 and the flanged edge of the strip 62 as the wire and strip wrap around the mandrel. It is a feature of the invention that the groove 142 has sloping faces which permit the upstanding flange of the preformed strip to bend partway over and outy of its original vertical position. This bending over of the flange prevents the ange from stretching4 and tearing when the strip is subjected to the strains incident to the shifting ofthe roller towardl and from the axis of the mandrel to follow the generally polygonal outline of the mandrel. In order to obtain economically the particular shape desired for the groove 142, the roller 101 is of composite construction with its cam portion 126 comprising a ring that is pressed over a reduced diameter portion of the body of the roller 101, and with the inner face of the ring forming one side of the groove 142. The roller 101 has ball bearings 146 for reducing its friction as it rotates about its axle 147. All of the other rollers around the mandrel have similar ball bearings although other types of bearings can be used.

A second groove 148 of the roller 101 guides the folded over edge of the preformed strip 62 into engagement with the ange of the next adjacent convolution of the strip `ou the mandrel 14. 'Ihere are other grooves 149 in position to receive subsequent convolutions of the seamed tube on the mandrel. The roller 101 and the other rollers, that are located around the mandrel 14, act in effect as a roller nut through which the tube screws as the mandrel rotates. The tube is thus stripped from the mandrel progressively as it is formed.

Figure 9 shows the roller 102 with a groove 152 that bends the flange of the metal strip back into a substantially vertically extending position. The bending of the ange after the strip is wrapped on the mandrel, and while the strip approaches the passes into the groove 152, permits the ange to be returned to its upright position without tearing because the pressure is applied gradually and substantially uniformly in a manner that permits cold ow of the metal of the strip.

A third groove 153 is not as deep as the corresponding groove 148 of the roller 101, and this groove 153 forces the folded edge of the strip toward the mandrel and starts the interlocking of the seam. Other grooves 155 correspond with the groove 149 of the roller 101 and the side Walls of these grooves serve to strip the tube from the mandrel in a manner already explained.

Figure 10 shows the roller 103 with a groove 162 for guiding the flanged edge of the metal strip and advancing the strip axially along the mandrel 14 in accordance with the progressive stripping action of the rollers, as previously explained. The next groove 162 is shallower than the corresponding groove 153 of the previous roller 102. Other grooves 165 serve to strip the tube from the mandrel.

The groove 163 is preferably shallow enough to bend the folded-over edge of the strip and its engaging ange all lthe way down to form an interlocking seam for the tubing. Y

'Ihe bottom of the groove 163 preferably rolls the interlocking seam against the wire 77 on the mandrel. The wire prevents the corrugation under the seam from being mashed down by the seaming operation and also provides lateral reinforcement against the axial pressure by which 8 the rollers strip the tube from the mandrel. A solder thread may be included in the seam, as it is formed, in accordance with conventional practice on spirally wound tubing.

The preferred embodiment of the invention has been illustrated and described, but changes and modifications can be made and some features can be used in dilerent combinations without departing from the invention as defined in the claims.

What is claimed is:

1. A machine for making helically wound non-circular tubing including a rotatable mandrel, guide means that supply preformed strip material to the mandrel at an angle that causes the strip to wrap as a helix, as the mandrel is rotated, with the adjacent edges of successive convolutions engaged with one another to form a seam, rollers at angularly spaced locations around the mandrel in position for operating on the helical seam, bearing means coaxial with the axis of the mandrel, a frame movable on said bearing means about an axis in substantial alignment with the axis of rotation of the mandrel, arms carried by the frame, means for effecting movement of the arms with respect to the frame toward the axis of the mandrel, one of said rollers being carried by each arm in a position to operate on the seam of the tubing which is formed by the wrapping of the strip on the mandrel, mechanism including an operating cam for oscillating the frame on its bearing, driving mechanism that imparts intermittent rotation to the mandrel, said driving mechanism including an intermittent motion device, and a continuously operating motor operatively connected with the intermittent motion device and with the mechanism for operating the frame and mandrel in timed relation with one another.

2. A machine for making helically wound, non-circular tubing as described in claim 1, characterized by operating mechanism for the frame which turns the frame in the same direction as the mandrel, but at a slower speed.

3. A machine for making helically wound non-circular tubing as described in claim 1, characterized by a mandrel having four sides with its adjacent sides of different width, and driving mechanism that imparts intermittent rotation to the mandrel.

References Cited in the file of this patent UNITED STATES PATENTS 185,514 Foglesong Dec. 19, 1876 657,878 Kirk Sept. 11, 1900 839,060 Dunn Dec. 18, 1906 958,767 Richards May 24, 1910 1,970,694 Fischer Aug. 21, 1934 2,158,401 Chamberlin et al. May 16, 1939 2,158,796 Harrah May 16, 1939 2,406,943 Carter Sept. 3, 1946 2,431,928 Garreau Dec. 2, 1947 2,440,792 Wyllie May 4, 1948 2,618,233 Padgett NOV. 18, 1952 

